Exceptionally well-acted, understated prison drama.Running time: 93 minutes. Rated R (violence, language). At the Cinema Village, 12th Street, between Fifth Avenue and University Place.‘ANIMAL Factory” is a wonderfully acted, strangely low-key prison movie, the very opposite of the gothic horror show that is HBO’s brilliant “Oz” (even though “Animal” director Steve Buscemi has been a director on that show).

Buscemi, who as an actor has been one of the glories of American independent film (he was Mr. Pink in “Reservoir Dogs,” for example), has directed one previous movie, “Trees Lounge” (1996), a classic little indie about an alcoholic and the Long Island bar where he hangs out.

With “Animal Factory,” Buscemi widens his canvas, but he shows the same intelligence, the same restrained touch, the same skill with actors.

Ron Decker (Edward Furlong) is a 25-year-old from the middle class sentenced to 10 years in Eastern State Penitentiary.

Small and good-looking, he’s an extremely vulnerable “fish.” But he’s fortunate enough to be taken under the wing of Earl Copen (Willem Dafoe), a longtime inmate who’s essentially the king of the prison yard.

Although Decker fears that Copen’s protectiveness is merely the older man’s means to an end – making Decker his “punk” – Copen’s motives are actually more complicated.

“I probably wouldn’t help you so much if you were ugly,” he says. “But that’s my problem.”

Both men have an incentive to stay out of trouble with the prison authorities: Copen is up for parole and Decker has a chance to get his sentence reduced.

But Decker’s youth and attractiveness mean trouble is coming their way. One form it takes is a particularly vicious redneck rapist played by, of all people, Tom Arnold.

It’s one of several superb performances that Buscemi draws from his fine cast, which includes Seymour Cassel and John Heard.

Dafoe, one of our best actors, is as intense, yet believable, as ever. Furlong shows that he’s more than a pretty face. But the biggest surprise comes from Mickey Rourke, unrecognizable and completely convincing as Decker’s drag-queen cellmate.

Buscemi builds tension with great skill, without resorting to graphic brutality.

But the film ends abruptly, and there are times during “Animal Factory” when the story feels like it’s been taken from another era, the era of “Shawshank Redemption.”